The invention relates to lysobactin amides and methods for their preparation, as well as their use for manufacturing medicaments for the treatment and/or prophylaxis of diseases, in particular bacterial infectious diseases.
The bacterial cell wall is synthesized by a number of enzymes (cell wall biosynthesis) and is essential for the survival and reproduction of microorganisms. The structure of this macromolecule, as well as the proteins involved in the synthesis thereof, are highly conserved within the bacteria. Due to its essential nature and uniformity, the cell wall biosynthesis is an ideal point of attack for novel antibiotics (D. W. Green, The bacterial cell wall as a source of antibacterial targets, Expert Opin. Ther. Targets, 2002, 6, 1-19).
Vancomycin and penicillins are inhibitors of the bacterial cell wall biosynthesis and represent successful examples of the antibiotic potency of this principle of action. They have been employed for several decades clinically for the treatment of bacterial infections, especially with Gram-positive pathogens. Due to the growing occurrence of resistant microbes, e.g. methicillin-resistant staphylococci, penicillin-resistant pneumococci and vancomycin-resistant enterococci (F. Baquero, Gram-positive resistance: challenge for the development of new antibiotics, J. Antimicrob. Chemother., 1997, 39, Suppl A:1-6; A. P. Johnson, D. M. Livermore, G. S. Tillotson, Antimicrobial susceptibility of Gram-positive bacteria: what's current, what's anticipated?, J. Hosp. Infect., 2001, (49), Suppl A: 3-11) and recently also for the first time vancomycin-resistant staphylococci (B. Goldrick, First reported case of VRSA in the United States, Am. J. Nurs., 2002, 102, 17) these substances are increasingly losing their therapeutic efficacy.
The present invention describes a novel class of cell wall biosynthesis inhibitors without cross resistances with known antibiotic classes.
The natural product lysobactin and some derivatives are described as having antibacterial activity in U.S. Pat. No. 4,754,018. The isolation and antibacterial activity of lysobactin is also described in EP-A-196 042 and JP 01132600. WO04/099239 describes derivatives of lysobactin having antibacterial activity.
The antibacterial effect of lysobactin and katanosin A is furthermore described in O'Sullivan, J. et al., J. Antibiot. 1988, 41, 1740-1744, Bonner, D. P. et al., J. Antibiot. 1988, 41, 1745-1751, Shoji, J. et al., J. Antibiot. 1988, 41, 713-718 and Tymiak, A. A. et al., J. Org. Chem. 1989, 54, 1149-1157.
The stability of an active ingredient is an important parameter for its suitability as medicament. The stability is important inter alia in the storage and administration of medicaments. Many natural products show a stability which is insufficient for medicaments.
The depsipeptide lysobactin which has antibacterial activity is hydrolyzed in an aqueous neutral to basic medium (pH>7) within days. The result thereof is “open-lysobactin” which is opened on the lactone and has no antibacterial activity. It is therefore desirable to have active analogs of lysobactin with greater ring stability.